Hi Tom . . .
Unfortunately, there are a lot of variables here. From what I have read flame speeds are dependent on fuel, additives, stoichiometry and turbulence or lack thereof (the so called Reynold's number). And I don't think the leap from theory to practice is all that straight forward.
Google books has got a very scholarly work online (Charles Taylor):
Internal Combustion Engines in Theory and Practice This author expresses flame speed in ratio to piston speed - his graph suggests that flame speed is not a constant in these calculations. (echoing strokersix's post)
regards,
stock49
